Pen



FIG. 1 is a front left perspective view of a pen showing our new design;

FIG. 2 is rear right perspective view of the pen shown in FIG. 1;

FIG. 3 left side elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a front elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a rear elevation view thereof.

The ornamental design for a pen, as shown and described.